Say i have a chemical bond such as H2O how could i just look at that formula and figure out if it is a...?

Question

How would i find if that is a ionic or covalent bond just by looking at the formula?

Answer 1

When you think ionic, think of metal bonded to non-metal.  Most exactingly, think positive polyatomic ion (or metal) bonded to negative polyatomic ion (or nonmetal).  Things like:

NaCl, NaI, NaOH, MgSO4, MgCl2, Fe2O3...

To get good at these decipher metals from nonmetals on the periodic table and memorize some polyatomic ions : sulfate, sulfite, nitrate, nitrite, hydroxide, hydride, phosphate, ammonium, etc...

When you think covalent, think nonmetal bound to nonmetal.  Things like:

CH4, H2O, H2, O2, N2, CH3CH2OH (ethanol, mmm..), etc...

Obviously, if you see a bunch of nonmetals and none of the usual suspects from above, metals and any of them polyatomics, then its covalent!  

This is of course an over simplification since even covalent compounds have ionic character, yada, yada!  But thats the quick and dirty ionic or not test you learn in general chemistry!

Answer 2

There is no sharp dividing line, but the more electropositive the one element is and the more electronegative the other is (in a compound of two elements, which is an oversimplification of the general case), the more ionic character the bond will have.  On the other hand, a bond between two atoms of the same element will be purely covalent.

In between, there are examples such as Al₂Cl₆ that are covalent but form ionic solutions in water.

Answer 3

these are things you have to memorize but it is covalent because ironic bods have a partial charge h20 is a strong bond  

Answer 4

Simple way: Metal+nonmetal=ionic

nonmetal+nonmetal=covalent

So looking at H2O we see that both H and O are nonmetals so this is covalent because nonmetal+nonmetal=covalent. Metals are on the left of the periodic table, after you pass that "staircase", metals are to the left of the staircase, nonmetals are to the right of the stair case. Hydrogen is the exception, hydrogen usually gets put with the metals but it's actually a non-metal.

It actually gets more complex than just metal+nonmetal=ionic and nonmetal+nonmetal=covalent.

If you want to be really accurate you have to figure out the bond polarity by finding the electronegativity differences. http://en.wikipedia.org/wiki/Electronega...

We only have one type of bond in H2O and that's an O-H bond. The electronegativity value of O is 3.44 according to wikipedia and the electronegativity value for H is 2.20 therefore the difference is 3.44-2.20=1.24

If the difference is less than 0.4 we consider the bond nonpolar covalent, if the difference is between 0.4 and 1.7 we consider the bond polar covalent, if the difference is greater than 1.7 we consider it ionic.

Since 1.24 is between 0.4 and 1.7 we consider the bonds in water polar covalent.

Answer 5

ionic, like salts, would be NaCl. This is bonding of a metal with a nonmetal. H2O consists of two gaseous elements bonded together in bent arrangement with covalent bonds.